# Risch algorithm

In symbolic computation, the **Risch algorithm** is a method of indefinite integration used in some computer algebra systems to find antiderivatives. It is named after the American mathematician Robert Henry Risch, a specialist in computer algebra who developed it in 1968.

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The algorithm transforms the problem of integration into a problem in algebra. It is based on the form of the function being integrated and on methods for integrating rational functions, radicals, logarithms, and exponential functions. Risch called it a decision procedure, because it is a method for deciding whether a function has an elementary function as an indefinite integral, and if it does, for determining that indefinite integral. However, the algorithm does not always succeed in identifying whether or not the antiderivative of a given function in fact can be expressed in terms of elementary functions.

The complete description of the Risch algorithm takes over 100 pages.[1] The **Risch–Norman algorithm** is a simpler, faster, but less powerful variant that was developed in 1976 by Arthur Norman.